1. Field of the Invention
The field of the invention relates to a dry lay process for forming a mineral wool fiberboard product from an intimate mixture of mineral wool fibers and thermosetting powdered binder entrained in an air stream which is exhausted through the lower and upper forming wires in a forming zone.
2. Description of the Prior Art
Low-density fiberboard products having excellent acoustical properties are readily available. Generally speaking, air laid products are formed from an intimate mixture of glass fibers and thermosetting resinous binders. However, although slurry board forming processes for manufacturing satisfactory low-density good acoustical fiberboard products from shorter mineral wool fibers are known, such shorter fibers present several problems relative to satisfactory mat and board formation using dry laid systems. Typical of the prior art in this field are U.S. Pat. Nos. 2,589,008; 3,356,780; 2,188,373; and 2,012, 805.